This collective operation marks the communication object for
deallocation. The handle is set to MPI_COMM_NULL.
MPI_COMM_NULL
Any pending operations that use this communicator will complete normally;
the object is actually
deallocated only if there are no other active references to it.
This call applies to intra- and intercommunicators. The delete callback
functions for all cached attributes (see Section ) are
called in arbitrary order.
callback function, delete
It is erroneous to attempt to free MPI_COMM_NULL.